Macropolycyclic ligands containing appropriate binding sites and cavities of suitable size and shape, may be designed so as to display molecular recognition in the formation of selective inclusion complexes, cryptates, with metal cations, but also with anions and molecules. Macrobicyclic ligands B form highly stable and selective alkali and alkaline-earth cryptates, displaying a pronounced cryp...

A new tris(pyrazolyl)borate ligand bearing phosphine donor groups appended to the 3-position of the pyrazolyl rings is reported, and the hemilabile behaviour of this tris-N,P ligand in coordination with K+, Tl+ and Cu+ ions is investigated.

The pyridoxal 5'-phosphate-dependent enzyme dialkylglycine decarboxylase (DGD) is activated by K+ and Rb+ ions, whereas Li+ and Na+ ions are inhibitory. A binding site for alkali metal ions close to the active site (site 1) was discovered in the crystal structure of DGD, and an exchange of K+ for Na+ at this site was shown to affect the conformation of two active site residues [Toney, M. D., Ho...

The gas-phase structures of alkali-metal cationized glutamine are investigated by using both infrared multiple photon dissociation (IRMPD) action spectroscopy, utilizing light generated by a free electron laser, and theory. The IRMPD spectra contain many similarities that are most consistent with glutamine adopting nonzwitterionic forms in all ions, but differences in the spectra indicate that ...

Guanine tetraplexes are biological non-covalent systems stabilized by alkali cations. Thus, self-clustering of guanine, xanthine and hypoxanthine with alkali cations (Na(+), K(+) and Li(+)) is investigated by electrospray ionization mass spectrometry (ESI-MS) in order to provide new insights into G-quartets, hydrogen-bonded complexes. ESI assays displayed magic numbers of tetramer adducts with ...

The aim of this project is the investigation of atomic and nuclear properties of heavy elements with charge numbers Z 100 by laser spectroscopy. Any atomic spectroscopy, even with the most sensitive laser methods, is seriously hampered by the fact that no information on the atomic structure is available for these elements. To get acquainted with such a spectroscopy experiments were performed fo...

The alkali-metal gold trielides K(3)Au(5)Tr (Tr = In (I), Tl (II)) and Rb(2)Au(3)Tl (III) have been obtained directly from the elements, and their orthorhombic structures determined by single-crystal X-ray diffraction means (I/II: Imma, a = 5.562(1), 5.595(1); b = 19.645(4),19.706(4); c = 8.502(2), 8.430(2) A; Z = 4, respectively; III: Pmma, a = 5.660(1), b = 6.741(1), c = 9.045(2) A, Z = 4). T...

a new cesium ion selective pvc membrane based on parent calix [4] arene was developed for potentiometric determination of cesium in environmental samples. the electrode based on p-5,11,17,23tetra(tertbutyl) 25,26,27,28-tetrahydroxy calix[4]arene(thc) as ionophor ,dibutyl phthalate (dbp)as plasticizer ,sodium tetra phenyl borate(natpb)and oleic acid as lipophilic salt and additive showed the bes...

a new series of noncyclic ionophores containing two to four furan units (ia to iiib) i.e. 1,1-difurylethane (ia), 2,5-bis(methylfurfuryl)furan (iia) and 1,1’ ethyledenebis[5-(methylfurfuryl)furan] (iiia), 2,2-difurylpropane (ib), 2,5-bis (dimethylfurfuryl)furan(iib), 2,2’-isopropylidenebis[5-(dimethylfurfuryl)furan] (iiib) have been synthesized by the condensation of furan with acetaldehyde and...